Floods devastated a large portion of Thailand’s rice bowl in the months of November and December 2011. In Chainat, the Rice Research Center was submerged and so was the Rice Department headquarters in Bangkhen, Bangkok and several other rice department research centers. In February 2012, spots of hopperburn were located in Chachoengsao,which was not affected by the floods and also in flood-affected Suphan Buri province, threatening to cause huge losses. In June 2011, Rice Department and the Thai Agricultural Business Association (TABA) together with IRRI jointly launched a campaign to stop the use of abamectin and cypernmethrin, two of the planthopper resurgence pesticides. However the on the ground activities to implement the campaign were hampered by the floods. The activities were revived in late January 2012 in Chainat but was not in time to stop the outbreaks from developing. Insecticide misuse had continued with abamectin and cypermethrin dominating in the sprays farmers use. A farmer in Suphan Buri said he sprayed cypermenthrin 7 times and his crop succumbed to hopperburn.

BPH outbreaks in fields of Pathum Thani province - 2012

The floods can affect planthopper populations but they affect the natural enemies even more. Most of the natural enemies’ habitats with shelter and food were submerged. In fact many of perennials on the bunds were destroyed. Planthoppers on the other hand are migratory and invaders into the new crops grown after the floods have lower natural enemy pressure. This coupled with the rice price support introduced by government in November 2011 which stimulated farmers to further increase inputs such as seeds, fertilizers and pesticides made fields extremely vulnerable to outbreaks. The rice price subsidy encourages farmers to focus on high production and not quality and thus higher inputs, which can cause other long term damage as well.

Table 1: Planthopper outbreak areas in Central Thailand in February – March 2012.

Dates

Number provinces affected

Rice stages when outbreaks occurred

Total area affected (ha)

< 40 days after sowing

41-60 days after sowing

> 60 days after sowing

8 Feb

11

336

2,536

8,268

11,040

29 Feb

15

5,732

80,901

107,498

155,299

7 Mar

14

4,793

35,790

62,837

103,260

14 Mar

17

3,813

58,139

92,165

154,117

Light trap records from Chainat Research Center for 2010, Jan and Feb of 2012

In mid March, 2012, the area affected has reached 17 provinces and covered about 154,117 ha. More than 60% of the outbreaks areas were in the later crop stages near harvesting in various degrees and about 5000 ha had complete crop failures. In Chainat Research Center, the light trap records increased from less than 300 in January to 300,000 in February, a 100,000 fold similar trend to that of 2010. As in previous years, after the huge BPH outbreaks the next season might be followed with very high infestations of the 2 virus diseases transmitted by BPH. Thus in the next few month we can expect more rice production areas destroyed by virus diseases as well as hopperburn. The rice bowl is now facing the 8th consecutive seasons of planthopper destructions.

From the outbreak records thousands of farmers had been affected and the total production loss may be equivalent to more than 200,000 tons of paddy. Hundreds of farmers could now be in debt from the crops they lost, financing inputs, credit and loans they obtained. Most farmers get their pesticides on credit from the local pesticide retailers who provide them with poor information and advice. Although the Rice Department has issued the banning of cypermethrin and abamectin from rice, these two insecticides are still being actively sold to unsuspecting farmers.